1. Field of the Invention
The present invention relates to a method for wrapping rolled material, particularly a roll or coil of metal, such as steel, aluminum, or other metal.
2. Description of the Related Art
In steel mills the steel is often made in sheets having a length many times greater than its width. The sheets are wound into coils for compactness during storage. The coils of steel may be stored on pallets for ease in moving and manipulating the coils. It is desirable to wrap the coils of steel in material which is relatively impermeable to water to prevent corrosion of the steel during storage and transport. The present invention relates to a method of wrapping steel coils in a material which is water resistant and which contains a volatile corrosion inhibitor.
Several methods of wrapping cylindrical objects and coils are known. U.S. Pat. No. 2,371,858, issued Mar. 20, 1945 to Tuthill, et al., describes a method of wrapping a roll of adhesive tape using two square sheets of cellophane by placing one sheet under the roll and wrapping the corners up the sides and extending over the top of the roll, placing the second sheet over the top with the corners of the second sheet between the corners of the first sheet, pulling the corners of the second sheet down the sides and under the bottom of the roll, and heat sealing with adhesive.
U.S. Pat. No. 4,565,049, issued Jan. 21, 1986 to DeLigt, et al., teaches a process for wrapping paper rolls which puts header sheets over the ends of the rolls, pulling the headers a short distance up over the rolls, pleating the headers, and securing the headers to the rolls by placing a strip of adhesive on the paper and pressing the headers against the paper, followed by capping the ends of the rolls.
U.S. Pat. No. 5,020,664, issued Jun. 4, 1991 to Hughes, et al. shows packaging a cylindrical broom with bristles inside a polygon shaped container with end caps which support the axial core of the broom so the bristles don't contact the package. U.S. Pat. No. 5,071,501, issued Dec. 10, 1991 to Doi, et al., discloses a method of wrapping a roll like article in which a core extends from both ends of the roll.
U.S. Pat. No. 5,477,659, issued Dec. 26, 1995 to Conrad, et al., describes another method for wrapping rolls of paper in which an inner end cover is affixed to a core by stapling or by nails, the roll is covered by a shroud which is wrapped and pleated over the ends, and outer end covers are glued to the pleated shroud, air being removed by heating during the process.
European Patent No. EP 538,907, published Apr. 28, 1993, and Japanese Patent 5-4627, published Jan. 14, 1993, show similar methods of wrapping annular ring shape articles with heat shrink packaging by wrapping a cylinder of material around the outside of the ring, folding the ends over the sides, passing metal rings through the inside of the article, and heat sealing the inside of the ring. Japanese Patent No. 3-29764, published Feb. 7, 1991, teaches a method of wrapping a coil of wire with covers using string to secure the covers.
My own prior patent, U.S. Pat. No. 5,657,613, issued Aug. 19, 1997, describes a method of wrapping steel coils with their axis of rotation parallel to the ground, involving folding and pleating a sheet of tear resistant material, punching a hole through the top and bottom ends, threading a first rope or string through the holes in the top end and a second rope through the holes in the bottom end, placing the coil on the sheet so that the ropes parallel the edges of the coil, wrapping the ends around the coil and securing them with adhesive tape, pulling the strings taut so that the ends of the sheet form a circle of smaller diameter than the core of the roll, and securing the ends of the sheets inside the core.
Various methods of making packaging materials which describe means for inhibiting corrosion include U.S. Pat. No. 4,290,912, issued Sep. 22, 1981 to Boerwinkle, et al. (a volatile corrosion inhibitor having (1) a polyolefin polymer, (2) an inorganic nitrite salt, (3) a trisubstituted phenol, and (4) fumed silica, in order to avoid problems with sodium nitrite in environments which lack carbon dioxide); U.S. Pat. No. 5,426,916, issued Jun. 27, 1995 to Grigsby, et al. (composite material impregnated with a liquid such as mineral oil which slowly releases and coats the article to avoid corrosion); and Soviet Invention Certificate No. 863,468 (a press filled with polystyrene foam tablets and smeared with an oil containing a corrosion inhibitor, the oil penetrating the foam and the inhibitor being baked into the polystyrene).
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus a method for wrapping steel coils solving the aforementioned problems is desired.